


Appropriate Sizes

by SexualPreferences



Series: Ganbare! KyoKen-Chan [3]
Category: Haikyuu!!
Genre: Anal Sex, Beta Yahaba Shigeru, Bottom Kyoutani Kentarou, M/M, Masturbation, Mpreg, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Kyoutani Kentarou, Omega Verse, Pregnant Sex
Language: English
Status: Completed
Published: 2017-06-06
Updated: 2017-06-06
Packaged: 2018-11-09 19:03:33
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,559
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11110893
Author URL: https://archiveofourown.org/users/SexualPreferences/pseuds/SexualPreferences
Summary: He's been looking forward to this.





	Appropriate Sizes

**Author's Note:**

> not-beta'd yada yada yada.

Kentarou checks off the calendar pregnancy calendar on his phone as soon as he wakes up in the morning, his mate snoozing away beside him.

 

Today marks the start of week thirteen of his pregnancy, the last week of his first trimester.

 

He checks the information of the app to learn new things about what to expect. He’d already begun to notice he was experiencing less severe and frequent symptoms last week, just like he had been told to expect. Though, there was still the weird cravings, mild (thank god) nausea, chest tenderness, headaches, and the really gross slimy clear discharge. He also got overheated way too easily. He’s been looking forward to finally being in his second trimester. According to Yamanaka-san, his Mommy buddy, second trimester would be the easiest on him symptom wise. Kentarou was pleased when told this and noticed he already had some of his energy back. He was so excited to not be a human mess anymore. His symptoms have been a living hell on him, emotionally and physically. He didn’t feel like himself and as often as him and Shigeru bicker and pick as a show of affection, though sometimes they genuinely are annoyed with each other, he almost always took it personally. He’d gotten clingy and weak feeling and turned into such a sobby sap.

 

He knew, realistically, there wasn’t anything to be ashamed of, that this was a normal part of motherhood, but he’s proud of how strong he normally is. He’s proud of how well he can do things without a mate, but by week nine of his pregnancy he had felt like he couldn’t do anything at all. Shigeru was also too protective for his tastes recently; not letting him lift anything heavier than a light grocery bag.

 

They’d actually had a pretty big fight about it the night before.

 

Kyoutani was pretty proud of himself for _not_ crying immediately for the first time in over a month. However, the novelty was lost when his mate went to bed without speaking to him. Before his mate went to bed, he’d been feeling big off his anger and pride, but after his mate was already fast asleep, and his own anger had died out a fraction, he felt bad. He didn’t like truly fighting with Shigeru. Shigeru was a good mate, and was very good to him. Shigeru didn’t treat him differently for being an omega and didn’t pull his verbal punches with him, even after discovering his pregnancy. The only time lately he was a pain in the ass was because Kentarou was up somewhere high or lifting something.

 

The more he thought about the fight last night, the sadder Kentarou became. Why did Shigeru have to become a pain in the ass about the one thing Kentarou felt the most proud of? His strength was one of his few good points damn it and now Shigeru wasn’t letting him have that and he just couldn’t understand why.

 

Kentarou sighed, getting out of bed. He might as well get ready for the day.

 

As he brushed his teeth, wanting to eat the entire tube of toothpaste, arms circled around his middle suddenly so he threw an elbow back in reflex. Shigeru give a breathless wheeze on impact. The omega turned around quickly, his mouth full of toothpaste so his words came out messy and garbled.

 

“Shorry!” he gargled, “Di’n mean fo!” The beta was never up and about this early and normally, if he was, he’d still be half-asleep at best.

 

Once Shigeru got his breath back, he stood back up straight and looked at the shirtless Kentarou.

 

“I wanna…talk about last night, okay?” He says, serious, “I’ll be in the bedroom when you’re ready to come talk. Go ahead and finish up here,”

 

“Ohay…”

 

Then the beta closed the bathroom door softly behind him on his way out.

 

Kentarou spit and rinsed and headed back to the bedroom.

 

 

 

 

 

 

Shigeru was sitting on the bed, cross legged and looking at his phone, when Kentarou came back into the bedroom. When he had heard Kentarou enter he put the phone down and looked very…Kentarou couldn’t figure what the expression was for the life of him. It looked seriously though, and it made him edgy.

 

Shigery patted the space on the bed in front of him, calling the omega over to him and Kentarou complied cautiously.

 

There was a drawn out silence after Kentarou had gotten comfortable. Kentarou desperately wanted his mate to say something as the silence dragged on into a full minute. Eventually, Shigeru took Kentarou’s hands in his, taking a deep breath in before speaking, “I don’t think you’re weak, Kentarou,”

 

Kentarou frowns, his face nearly pulling into a glare. His mate’s behavior indicates otherwise.

 

“You’re not weak,” Shigeru says again, “but our _baby_ is,” Shigeru squeezes his hands.

 

“But-“

 

“Please,” He says, “Let me finish,” Then Kentarou falls silent, ready to hear what his mate has to say. “After you told me, I looked up all the things I could so I could keep you comfortable and happy while you carry my child… But… I found some scary things too. Terrifying things,” Shigeru’s thumbs rub circles on the back of Kentarou’s hands, “About pregnant mates’ placenta detaching and losing their babies because the fell from a ladder, trying to change a light bulb, or carrying too many grocery bags at once. There were posts from omegas and betas and alphas all saying, ‘I thought I was strong enough and this wouldn’t happen’ or ‘my mate miscarried and blames themselves, what do I do?’ And I honestly couldn’t answer that question myself. What would I do if something like that happened, and you… became different because of it?” Shigeru puts his forehead to Kentarou’s and breaths in his scent, trying to steady himself, “Kentarou you’re strong, you do most of the heavy lifting in this house, but our baby isn’t strong. Our baby is just a tiny…how big is our baby now?”

 

“Our baby is the size of a lemon,” Kentarou whispers.

 

“Our baby is just a tiny lemon. I should have explained this to you better last night, instead of getting mad, but, I thought you were just being stubborn. I thought maybe you already understood why I was so terrified of you pushing yourself too much,” Shigeru places a hand tenderly on Kentarou’s, now, slightly showing belly, “I’m sorry,”

 

Kentarou sighs and looks away from his mate. He gets why his mate was worried and why the beta has been overbearing and fussy. He’s also at fault here, for not telling Shigeru everything the doctor tells him he can do. Kenarou admits to himself that, yes, he did take his frustration of not feeling like himself out on Shigeru but he’s just so used to being able to go ahead and do something by himself, and not waiting around for help. He’s too impatient for that.

 

“Listen, my doctor said that I can lift things as long as I’m very careful and listen to my body. It stresses me out to no be able to do _anything_. I know you’re scared, I’m pretty fucking terrified myself, but I ask my doctor lots of questions. I don’t wanna mess this up any more than you do, alright? The doctor says exercise is good for me and the baby. I shouldn’t lift a couch or anything, but I can certainly carry grocery bags home alone and pick Momo up if I’m careful,” Kentarou turns, flopping backwards against his mate before laying his hands on his small bump, “I took out my stress on you and I’m sorry for that, But despite being pregnant, I do still need some space. I’ll let you know if anything’s wrong but you gotta trust I’m listening to my doctor,”

 

Shigeru lays his hands on Kentarou’s, lacing their fingers together as they rest on Kentarou’s stomach, “Okay… Just… Tell me if I’m getting too clingy. I can’t help wanting to be around you all the time and pamper you right now. You’re doing all the work of building a person. Our little person. So I really want to spoil you and make you comfortable,”

 

Kentarou snorts, “I don’t mind being pampered and spoiled, just, for the future, don’t tell me what to do. Rather, don’t tell me _not_ to do something unless I’m seriously being an ass,”

 

Shigeru kisses the side of his head, “Deal,”

 

 

 

 

 

 

As the week carried on, Kentarou felt his energy return tenfold.

 

The moments when he felt the best, he made sure to knock off a bunch of stuff on his to-do lists. At least stuff that he has set as reminders on his phone. Pregnancy brain is a helluva thing.

 

He talks to his boss about what he should do, he wasn’t fully comfortable telling his boss about him being pregnant yet, he hasn’t even told his mother, but he needed to know that Kentarou could no longer work with bigger animals at the clinic. He cheered and congratulated Kentarou, telling him that he could work with small dogs and cats for now and work the desk later in his pregnancy. His hours had also decreased. This eased a lot of Kentarou’s fears about having to start from scratch in his apprenticeship; reduced stress gave him more energy.

 

He goes to City Hall and registers for his Baby Badge, the badge he can strap onto his bag or hoody that gives him priority on trains and in lines. He’s starting to show now, so people take the badge a bit more seriously. An unfortunate draw back of his badge is that every old person that has ever given birth decided their advice is important enough to stop him and listen to. He glares off the ones that look like they’re going to chastise him. Its fucking June and he’s an oven, he will not being wearing thirty layers to keep his belly warm.

 

He also looks into some birthing classes; calling Yamanaka-san for advice to see what kind might be the best for him. She had asked him to join her at the one she was attending currently to see if it was something he’d like. He had plans to join her on Saturday.

 

Shigeru sets up doggy classes for Momo- ones that help her prepare for a new baby. Kentarou takes her to work with him one day to get her vaccinations up-to-date. Big sister needs to be ready for baby too.

 

There’s still so much to do even after getting all these things out of the way. It doesn’t feel like there’s nearly enough time to do all the important stuff. They haven’t told their families or friends yet. Kentarou was insistent they wait until he was into his second trimester before telling them. He didn’t want to get anyone’s hopes up, as much as his are, only for him to lose the baby. Plus, Shigeru’s mother was a terrible nag.

 

Granted, his new OB had told him he and the baby were very healthy.

 

There was just so much to do and its stressing him out. His weird vivid dreams weren’t helping either. Yamanaka-san had told him weird dreams were normal to have while pregnant, but having a dream that he gave birth to Momo was just too much.

 

Eventually, Shigeru sat him down and told him he doesn’t need to do it all right now and that he can take care of a lot of it when its gets to be too much. He’d wanted to argue but Shigeru put his foot down and told him stress would make the baby uneasy and Kentarou definitely didn’t want that.

 

They discussed how to divide up more of the workload between themselves, though Kentarou wanted to do most of it and there were things they could only do together.

 

In the end, he let Shigeru take care of the financial planning. He doesn’t think his pregnancy brain will let him numbers anyway.

 

 

 

 

 

 

It’s Friday evening of his thirteenth week when it happened the first time. He was rubbing lotion on his stomach and chest, they had been itchy and he’d been told by his OB not to scratch, when he was just suddenly really fucking _horny_.

 

He’d had no desire for sex since, what he assumed, was week six of his pregnancy. But, now, here he was, rarin’ to go and home alone with no mate to stuff him full.

 

He’d been told, by his app, he might experience a higher sex drive after the worst of his symptoms wore down. He’s been looking forward to it.

 

“Finally,” He groaned, letting his slick hand slide down to his cock, teasing the tip with his index finger. It felt good but he was in no mood for teasing himself right now. His skin felt heated and his felt his ass begin to slicken up. It was frustrating.

 

This was more bearable than his heats were, he thinks, kicked off his sweats and boxer briefs- a long clear line of slick attached to the liner.

 

Fisting his cock, he pumped slowly, letting himself enjoy the sensation. It’s been awhile since he’s last been in the mood. He feels more sensitive and raw as his languidly pumps at his cock, speeding up the slicker his dick gets with lotion and pre-cum. Normally, he’d also play with his nipples, but they’re itchy and sore right now; he’s not going to risk killing the first brush with arousal he’s had in over a month. Instead, he opts to let his free hand play with his balls, perineum, and asshole. The slickness making everything glide and he dips a finger in, pulling It out to massage his perineum then delving back in more deeply.

 

It all feels fucking amazing.

 

His ass is letting his fingers in easy, due to the incredible amount of slick and the thick discharge, and his cock is screaming at him for release. He moves his hand and fingers faster, chasing the peak of orgasm that keeps eluding him.

 

He keeps trying for close to thirty minutes.

 

The bedroom is filled with the echoes of squishing slick and frustrated moaning.

 

He can’t seem to come to climax at all. He’s tried everything that normally gets him off alone. It all feels good but he just can’t seem to cum at all. He’s so frustrated he wants to cry as his fingers still pump in and out of him and his hand fists his cock rapidly.

 

He wants Shigeru to hurry home. To fill him up and satisfy him.

 

After trying fruitlessly for another 10 minutes, he gives up with a huffed out little sob. If he keeps going he’ll only wear himself out for nothing.

 

In the end, he gets up, wipes himself dry, forgoing clothing entirely, before heading to the fridge to snack on pickled daikon.

 

He’s still naked when Shigeru comes home.

 

“I’m home!”

 

“Welcome home, Papa,” Kentarou calls back to his mate.

 

The beta steps out of the genkan to catch an eyeful of pregnant naked omega, sitting at the table, and eating pickled daikon out of the tub with chopsticks.

 

Kentarou watches as his mate scents the air of their apartment, his eyes dilating as the scent of Kentarou’s arousal floods his nose. Kentarou puts the tub of daikon down on the table and slinks his way over to his mate, grabbing him by the tie and pulling him down for a kiss. The beta is clearly confused but gives him what he wants by deepening the kiss, pulling the omega close to him making Kentarou to shiver.

 

Shigeru smells so fucking good.

 

“Come,” Kentarou orders, his dick hard and ass wet anew, “You’re gonna fuck me ‘til I scream,”

 

Shigeru flaps his mouth open and closed for a moment before giving the omega a mock salute and being pulled to the bedroom.

 

 

 

 

 

As soon as their bedroom door swings open, Kentarou begins pulling off every piece of clothing his mate has on. He gets fed up with the buttons of the beta’s shit after flinging his tie across the room, and just attacks Shigeru’s pants instead. Once the pants drop the floor, Shigeru pulls Kentarou up by the back of the neck, kissing him roughly, like a man starving. Kentarou moans into the kisses, his fingers greedily stroking at Shigeru’s dick through his boxers.

 

Shigeru bites at Kentarou’s lips, lifting him by the backs of his thighs, and lays him on the bed. Kentarou pushes at Shigeru’s boxers, attempting to get the down before pushing at them with his thighs.

 

“Get ‘em off,” Kentarou growls, not threating, but in frustration at the offending clothing preventing him from getting that dick inside as fast as possible.

 

Shigeru sits up on his knees, Kentarou looking up at him from his back on the bed, unbuttons his shirt and pulls down his boxers; his dick bounces free and Kentarou’s mouth waters. He reaches out and runs his fingers over the head of his mate’s cock watching the beta shudder and breathe out shakily. At the sight and smell of his mate coming apart from his touch, Kentarou feels a trickle of slick drip from his ass and onto the bed.

 

“C’mere,” Kentarou says, opening his arms up, becoming his met into them. Shigeru complies, draping himself over Kentarou, kissing his neck and rubbing his scent all over him. Kentarou sighs happily and embraces his mate close, rubbing his own scent onto the beta and pulling at this shirt his mate is still goddamn wearing. Thankfully, it’s now unbuttoned making it easy for Kentarou to pull it off his mate.

 

Full skin on skin feels much better.

 

Kentarou grinds upwards against Shigeru, their dicks frotting together making them both moan loudly. Shigeru reaches down, fingers dancing passed Kentarou’s swollen stomach, to tease the omega’s ass with his fingers before plunging them inside his mate.

 

Kentarou keens, arching his back and burying his fingers into Shigeru’s hair,

 

“I got you, Ken-chan,” Shigeru whispers, spreading and twisting his fingers into Kentarou’s dripping anus before removing them, “I’ll take good care of you. Mind getting on your side?”

 

Kentarou whines as the fingers leave him, unwrapping his legs from around Shigeru’s waist and turning on his side. He feels Shigeru lay behind him, taking a grip on one of his thighs and spreading his legs. Kentarou turns his head, lifting his arm, and puts his hand behind Shigeru’s head to pull him forward into a kiss. Shigeru presses the head of his dick to Kentarou’s hole.

 

“I’m going in now, ‘kay?” Shigeru whispers to him, and Kentarou nods his consent.

 

“Do it,”

 

They both moan as Shigeru pushes in. Kentarou’s head goes backwards into Shigeru’s shoulder and the beta wraps his arms around the omega, holding him tightly, one hand resting on the swell of his mate’s stomach and the other rubbing gently at the Kentarou’s chest.

 

Kentarou is in heaven.

 

He’s pushing his hips backward, meeting Shigeru’s thrusts, trying to encourage his mate to go faster, harder. He wants more. The roomed is echoing the sounds of their coupling; the slap and brush of skin-on-skin, the squelching noises his ass is making as his mate pushes into him, over and over, as well as the wet smack of kissing. Their moans are bouncing off the walls and Kentarou is thankful they soundproofed this room for his heats.

 

Shigeru’s thrusts speed up, his hand sliding down off Kentarou’s belly and onto the omega’s cock. Kentarou’s chokes out a throaty moan, pulling at his hate’s hair as he meets his mate as the beta pushes forward roughly- losing rhythm.

 

“Feels good,” Kentarou moans, “Harder, Shigeru. Make me- Ah- ah- AH!” Shigeru is mouthing at Kentarou’s mate mark. The skin on the back of his neck tingles, his bond with Shigeru humming and his stomach drops when his first orgasm in over a month washes through him, sending his head spinning. The beta keeps thrusting into him, extending his orgasm, his pregnancy and the long-overdue fucking making him hyper-sensitive.

 

Kentarou is screaming, his cock no longer fully hard but the hyper-sensitivity bringing him to his first “dry” orgasm outside of heat. His cock gives a pathetic little twitch when he feels the beta’s cum splash his insides.

 

As they relax against each other, catching their breaths, Kentarou feels his mate kissing at his bond mark again. Their hands are still linked over the small bump of his belly and he turns his head to kiss Shigeru on the mouth. Shigeru pulls out of him- he feels sated, relaxed, and well loved. This is just what he needed.

 

“What brought this on?” Shigeru asks as they cuddle, rubbing their scents all over each other.

 

“Increased sex drive. I suddenly got really, _really_ horny, _really, really_ fast,” He breaths, “I tried to get myself off but nothing was working. Sorry I kinda strong armed you into this but I needed this badly,”

 

Shigeru laughs through his nose at him, causing him to scowl. He doesn’t see how this is funny.

 

“You have no idea how much I’ve been wanting to ravish you,” the beta is running his hands all over Kentarou’s torso, “You’re stupid erotic,”

 

“Shut up,” Kentarou huffs, kissing him.

**Author's Note:**

> No new updates on world building.
> 
> They'll be telling friends and family next chapter, so look forward to that.


End file.
